The principal objective of the Biostatistics Core will be to provide project investigators a centralized resource for statistical expertise. Statistical issues will be addressed at all levels of investigation: from the design of experiments, to the maintenance of data quality, and the description and inferential statements made from the collected data. In support of this objective, the specific aims of the Biostatistics Core include: 1. To collaborate with project investigators in the formulation of hypotheses and hypothesis testing strategies, the design of experiments, Phase l/lltrials, and human subjects studies. To conduct and direct the statistical analyses of data generated by project investigators including: descriptive summary statistics, data modeling, experimental data inference and decision making. To insure that statistical principles associated with modeling nuisance or block effects, minimizing inference errors (Type I and II error) by correcting for multiple comparisons and multiple measures, randomization of conditions, and decreasing measurement error are employed in all studies. To collaborate with the Mouse Core director to ensure the above principles are used in obtaining reliable data from fully powered and unbiased designs. 5. To provide design expertise and oversight for the Phase l/llTrials. 6. To investigate or develop new statistical methodologies to directly address difficult data or design problems. To provide assistance in developing and implementing data management systems to allow investigators to effectively and efficiently manage and analyze their data,